I’m sure many of us know by now where the word “Halloween” comes from. It’s short for All Hallows’ Eve, the evening before All Hallows’ Day.

So what is All Hallows’ Day? “Hallow” is an archaic term, a noun meaning saint or holy person, so All Hallows’ Day is All Saints’ Day. This is the name that the religious observance on November 1 is better known by. (Today we really only use the verb “hallow,” which means to make someone or something holy.) On All Saints’ Day, the day after Halloween, Christians celebrate the saints and martyrs who have ascended to heaven. It’s also a time for them to remind themselves how they should strive to live.

All Souls’ Day follows on November 2. Both feast days originate from the earliest time of the Catholic Church in the 4th century. However, the date for All Souls’ Day was established only seven centuries later by Saint Odilo of Cluny, a Benedictine abbot, for his own monastery in France. The practice then caught on and was adopted by the Church.

On All Souls’ Day, believers pray for the dead, especially deceased loved ones. Unlike saints and martyrs, the souls in question are still in purgatory, awaiting their entrance into heaven. Food is prepared and left on their graves along with candles. Although this is mainly a Catholic tradition, other Christians also choose to observe All Souls’ Day.

The Mexican Día de los Muertos (Day of the Dead) is a particularly well-known version of All Souls’ Day. It evolved when the Spanish brought their religious customs to Central and South America during their conquest of the New World in the early 16th century. The Christian remembrance of souls naturally combined with the ancestor worship of the Aztecs and other native civilizations. As a result, festive parades and decorated shrines are a prominent feature of the day, and skulls and skeletons can be seen everywhere as symbols of death and rebirth. Unlike the spooky symbols of Halloween, these icons carry a more personal meaning because the day is a celebration of one’s family – those who have passed on as well as those still alive. The tone of the day, however, is one of joy and revelry, which is what makes it different from the more somber All Souls’ Day.

Halloween derives from Samhain, a Celtic festival celebrating the bounty of the earth. All Souls’ Day is the last day in the trio of remembrances of the spirit world. That such a day should fall in early November makes sense, as the earth now enters into a death-like state until its rebirth in the spring.